Tayside Diabetes MCN Handbook
Management of Intercurrent Illness in Type 1 Diabetes


THE GOLDEN RULE: Insulin should NEVER be omitted due to the risk of Diabetic Ketoacidosis (DKA)

The stress response to illness can lead to hyperglycaemia therefore during illness more monitoring, more fluid and generally more insulin is required. ALWAYS check for ketones to detect/exclude risk of DKA.


Indications for hospital admission

  • Inability to swallow or keep fluids dow
  • Persistent vomiting
  • Persistent diarrhoea
  • Strongly positive ketonuria/ ketonaemia with or without hyperglycaemia
  • When ketoacidosis is clinically obvious i.e. dehydration, abdominal pain, intractable vomiting, rapid or laboured respirations
  • Ketosis and diabetes in pregnancy


Food and Fluids during Illness

  • Maintain an adequate fluid intake (sugar free) of 100-200mL (approximately 1 glass) every hour
  • Maintain a regular intake of carbohydrate, regardless of glucose to facilitate insulin administration; insulin is required to correct ketosis.
  • At mealtimes, if unable to eat, but tolerating fluids, take carbohydrate in the form of 200mL of the following: pure fruit juice, ribena, milk, milk with drinking chocolate or ovaltine, (flat) Coca Cola or Lemonade (sugary).
  • If vomiting, consider an anti-emetic injection.  Provide with 'Dioralyte' or 'Rehidrat'.  Instruct to reconstitute as directed and to take an egg-cupful every 10 minutes.
  • Hospital admission is indicated if unable to swallow or keep fluids down (view below).


Blood Glucose Monitoring

  • Ensure that glucose monitoring technique and equipment is accurate and available.
  • Increase the frequency of blood glucose monitoring to at least 4 hourly.
  • Facilitate insulin adjustment advice.
  • Arrange to review results with patient.  See contact numbers for Diabetes Specialist Nurses


Ketone Monitoring

  • Check ketones in patients who are acutely unwell, vomiting, and/or during pregnancy irrespective of BG level
  • An elevated ketone result identifies the risk of Diabetic Ketoacidosis (DKA)
  • All people with type 1 diabetes (and/or their carers) should be informed and educated in ketone monitoring
  • Ketones should be checked 2 - 4 hourly during acute illness
  • Ketostix (Bayer Diagnostics) reagent strips for urine testing
  • Optuim β-ketone test strips for blood ketone testing with Optium Neo meter (Abbot) and Libre reader
  • Glucomen Areo 2K ketone sensors for blood ketone testing with Glucomen Areo 2K
  • Ketonuria / ketonaemia is an early sign of decompensation and if acted upon promptly, it can often prove possible to avert hospital admission (view below) Algorithm for Hyperglycaemia in Adults (view link)


Interpretation of ketone results during illness

Blood ketone level
Blood ketone level less than 0.6 mmol/L

This is within the normal range.

During illness test again in 2-4 hours to re-assess.

Blood ketone level greater than 0.6 mmol/L
Consider extra insulin by increasing routine insulin dose by 10% if blood glucose levels are elevated.
Consider STAT dose of rapid acting insulin (see below)
Recheck blood glucose and ketone level again in 1-2 hours to assess.
Ask the patient to drink water/sugar free fluid 100-200mL per hour


SGLT2 Inhibitors ('gliflozins' and Diabetic Ketoacidosis (DKA)


  • DKA has been reported in people taking SGLT2 inhibitors
  • Provide ‘sick day’ advice to all people prescribed SGLT2i to recommend stopping these drugs during intercurrent illness, in particular if there is a risk of dehydration
  • Ketone testing is essential as euglycaemic DKA can occur
  • Hydration, glucose and ketone monitoring is essential to inform treatment requirements
  • Facilitate insulin adjustment guidance

Please follow this link for more information


Ketone monitoring in blood compared with urine ketone testing


Blood ketone meter and urine dipsticks measure different ketone bodies.          

Blood ketone testing identifies the ‘immediate situation’ and is more reliable than urine ketone testing which provides ‘retrospective’ information. Blood ketone meters measure β-Hydroxybutyrate and this is the predominant ketone in DKA. Urine dipsticks measure acetoacetate, hence a negative urine ketone result does not rule out ketosis. It is important to note that during treatment for DKA conversion of β-hydroxybutyrate to acetoacetate may initially result in a paradoxical rise in urine ketones. Blood and ketone testing therefore are not strictly interchangeable.


 Insulin Management

  • Extra Doses of rapid acting insulin are often required during illness

  • During illness extra insulin can be administered 2-4 hourly to address elevated blood glucose levels (in addition to routine insulin doses)

  • This advice applies to adults; for children under the  age of 16 years, contact the Paediatric Diabetes team

  • Agorithm for Hyperglycaemia in Adults


  • More insulin is often required during illness

  • Increase routine insulin by 10% if the trend of recent blood glucose levels are elevated link to basic insulin adjustment

  • Insulin is required to correct ketosis

  • If ketosis is evident with low or normal blood glucose levels (e.g. in patients who are vomiting), IV fluid and insulin is indicated and patient should be admitted to hospital

  • Always recheck blood glucose and ketones within two hours to assess improvement or deterioration



Guidance for calculation of extra rapid acting insulin during illness


Increase ‘usual’ insulin by 10% if the recent trend of BG >10mmol/L

Extra insulin can correct hyperglycaemia and clear ketones


Use short acting insulin for STAT dosing e.g. Actrapid/ Novorapid/ Humalog/ Apidra

  • Calculate STAT dose as 10 - 20% of the patient’s total daily dose of insulin
  • For example: if the total daily insulin dose is 40 units, 10 -20 % will be a dose of 4 - 8 units
  •  Recheck blood glucose and ketones in 1-2 hours
  • STAT doses can be repeated at intervals of 2-4 hours if needed

OR some patients will calculate a correctional insulin dose 

An example of this:

100 divided by total daily insulin dose e.g.

  • If the total daily insulin dose is 50 units
  • 100 divided by 50 = 2
  • Therefore assume 1 unit of insulin will reduce (correct) the blood glucose by 2mmol/L
  • Example: if the blood glucose level is 20 mmol/L, assume 5 units of rapid acting insulin will correct blood glucose to 10mmol/L
  • Aim to correct blood glucose to 10mmol/L during illness
  • Blood glucose monitoring will identify the efficacy of this management


Continuous Subcutaneous Insulin Infusion (CSII) Pump therapy


The use of insulin pumps by people with type 1 diabetes is becoming increasingly common. The risk of DKA is greater in pump users as the pumps deliver a relatively small amount of rapid acting insulin continuously. Pump users do not use long acting basal insulin, thus there is never a reserve depot of subcutaneous insulin in the circulation.


The majority of users are competent in managing their diabetes and adjusting bolus doses according to the carbohydrate content of their food and maintaining basal insulin delivery rates by programming their pumps. Basal rates can be increased on a temporary basis to address issues with hypoglycaemia and hyperglycaemia.


In the event of hyperglycaemia/during sick days pump users should check for ketones. Extra bolus correctional bolus doses can be calculated and delivered to correct hyperglycaemia/ to correct ketosis.


There is a risk that insulin delivery from the pump can be interrupted due to problems with the subcutaneous infusion set. In the event of hyperglycaemia with ketosis or unresolved hyperglycaemia in spite of correctional bolus insulin via pump the pump users must change their infusion set and review glucose and ketone levels. All pump users should keep a supply of insulin devices so that subcutaneous injections of basal and bolus insulin can be injected in the event of pump failure. Additionally, It may be necessary to change to subcutaneous insulin by injection if the person is too unwell to self manage the pump.


Technologies such as flash glucose monitoring or continuous glucose monitoring systems are used by many people with type 1 diabetes as an essential aid to balancing food, activity and insulin dosing. Libre readers can be used with Abbott optium neo strips for finger prick blood glucose and ketone testing.


Pump Sick Day Rules

Medicines Sick Day Rules (Renal)

Follow up and Advice

The Hospital Diabetes Team is available for advice via hospital switchboard

Specialist Registrar for diabetes bleep 5416 or tay.diabendoreferrals@nhs.scot


Diabetes Specialist Nurses can provide ‘sick day rules’ advice and follow up (link to DSN contact details)

Telephone contact details for Diabetes Specialist Nurse Team

Mon – Fri 09.00 - 17.00 (24 hour answering machine)

  • Ninewells healthcare professional tel. 01382 496431 or 01382 632293
  • Perth Royal Infirmary healthcare professional tel. 01738 473976 or 01738 473476
  • Abbey Health Centre, Arbroath tel. 01241 447811